ACER’s 2025 activities supported more integrated EU energy markets
What is it about?
The 2025 Consolidated Annual Activity Report outlines ACER’s regulatory work and achievements over the year. It also reviews how ACER delivered on its 2025 work programme.
The report highlights ACER’s role in advancing the integration of the EU’s electricity and gas markets while safeguarding market integrity through surveillance activities under REMIT (the Regulation on Wholesale Energy Market Integrity and Transparency).
It was adopted by ACER's Administrative Board on 28 May 2026, following approval by the Board of Regulators.
What were the main developments in 2025?
- Electricity markets: After several years of preparation, 2025 marked the launch of the 15-min market time unit for day-ahead and intra-day markets to better integrate renewable energy sources. Linked to this, ACER also worked to further foster demand response and flexibility, monitored related market barriers and the integration of additional transmission system operators (TSOs) into EU balancing platforms. During 2025, ACER also contributed to the investigation of major incidents, including the Iberian blackout. ACER also continued working on the implementation of the Network Code on Cybersecurity related to cross-border electricity flows.
- Gas and hydrogen markets: ACER took up new tasks under the recast Gas Regulation, focusing on the new provisions and advancing gas decarbonisation and the hydrogen market. This included developing a cost-efficiency comparison framework for natural gas TSOs and revising the Capacity Allocation Mechanisms and Interoperability Network Codes. ACER also continued to monitor wholesale gas and liquefied natural gas (LNG) markets and expanded its hydrogen market monitoring.
- Infrastructure & security of supply: ACER continued to assess EU infrastructure planning and possible improvements to the process, as set out in several opinions and reports. Other key monitoring reports identified best practices on transmission and distribution tariff methodologies. ACER also monitored security of supply within Europe and approved the European Resource Adequacy Assessment. A new workstream on flexibility was launched, with a first milestone reached in 2025 through ACER’s Decision on an EU-wide methodology to assess flexibility needs in Europe.
- REMIT: ACER continued to improve and expand its market surveillance activities. In 2025, over 14,000 alerts were screened for potential market abuse and more than 1,300 cases shared with national regulatory authorities, leading to over €13 million in fines. ACER also collected more than 19 billion transaction records and published its first surveillance performance reports. It supported the implementation of revised REMIT and the European Commission’s preparation of the REMIT Implementing Regulation, as well as the Delegated Act for registered market participants and inside information platforms. ACER also launched the new REMIT Data Reference Centre and Inside Information Access Point.